Factors affecting the catchability of reef fishes in Antillean fish traps

Factors affecting the catchability of reef fishes in Antillean fish traps were investigated by experimental fishing on Barbados west coast fringing reefs. The species characteristics investigated included mobility on the reef, activity within the trap, gregariousness, and capacity for squeezing through mesh. The catchability of the study species varied considerably. Long term mobility was positively correlated with ingress and catchability, indicating that more mobile species are more likely to encounter and hence enter traps. No other effects of species-specific characteristics on catchability were detected. The presence of prey in traps increased the catchability of piscivores by lowering piscivore escapement, and the presence of piscivores in traps decreased the catchability of prey by lowering prey ingress, but the effects were weak in both cases. Catchability was negatively correlated with the percent reef cover of the substratum and with substratum rugosity, suggesting that traps are more attractive to fish in areas of low habitat complexity. Consistent with this, although fish density was higher at sites with greater habitat complexity, catch rates were not.